To Sister Norma Pimentel, it sounded like a golden opportunity to touch the heart of a president, to give him a firsthand account of the suffering she sees every day.

The night before President Trump’s Thursday visit to McAllen, Tex., Sister Norma, executive director of Catholic Charities of the Rio Grande Valley, got a call from the Border Patrol, inviting her to join the president at a roundtable discussion.

It was understandable that she would be asked to be a part of anything that purports to be a serious, high-level discussion of immigration issues along the U.S.-Mexico border.

Sister Norma is something of a local hero, loved and respected for the respite center that she runs near the McAllen bus station, working with law enforcement and an army of volunteers to help hundreds of desperate migrants every day. These people are in this country legally, most of them wearing electronic ankle monitors, as they await a court hearing on their requests for asylum.

Even Pope Francis has hailed her work, singling her out in a 2015 broadcast. “I want to thank you,” said Francis, “And through you to thank all of the sisters of religious orders in the U.S. for the work that you have done and that you do in the United States . . . is it appropriate for the pope to say this? I love you all very much.”

Sister Norma had written an open letter to Trump, which was published by The Post, imploring the president to see her respite center for himself, and to meet some of the people who come through: “Some days, we see 20 people. Other days, it’s closer to 300. In recent weeks, it has been very busy. Some stay a few hours, but many spend the night before heading on to new destinations. Since we opened, more than 100,000 have come through our doors.”

Still, if that couldn’t happen, this was surely the next best thing.

Or so she had hoped.

Sister Norma showed up as she had been instructed to do, at 11 a.m. sharp. The president arrived two hours later.

Sister Norma Pimentel, left, director of Catholic Charities for the Rio Grande Valley, at a border security event in McAllen, Tex., that President Trump visited on Jan. 10. Pimentel did not meet with Trump as planned. ((Courtesy of Diocese of Brownsville))

But instead of having an opportunity to speak with him as she had expected, the nun found herself sitting silently near the front of a stage-managed event featuring politicians, law enforcement representatives, a rancher and two relatives of fallen officers.

All those people’s points of view are important, of course, but there was no one on the roundtable who could speak from experience about what it is like to deal with the ongoing human needs of migrants.

The only pastor in the group, the Rev. Ramiro Peña, was from Waco — nearly a 6½ -hour drive away. His contribution to the conversation was to heap praise on Trump.

Before Trump had gone to McAllen, he had reportedly dismissed the whole trip as no more than a photo opportunity, foisted upon him by the White House communications operation.

Apparently, that was indeed the case. And Sister Norma — who wears a navy-blue habit and a large wooden cross that she carved herself around her neck — was there to add to the visual.

She was tempted to speak up, she told me, “but I did not. You know, I thought that it was not part of what he had planned.”

“I don’t know that he came away with anything other than a reaffirmation of what he wanted to do, as far as his reasons for [building a] wall. He made sure that the right people were at the table to support him on that,” she said.

“I think that if he came to the Rio Grande Valley to become aware and understand our reality here on the border, I think our local leaders would have had something to tell him that he needed to know about,” Sister Norma added, “what is our experience on the border here, and what has happened, how we see what’s happening. And so he didn’t care to hear from us.”

Indeed, it was a day of missed opportunities.

The president’s roundtable at the Border Patrol’s McAllen station was only a few blocks away from the processing center where children separated from their parents were held last year in cage-like enclosures.

When my Post colleague Philip Rucker asked Trump whether he planned to stop by that notorious site, the president answered: “I would do it. I would stop there if we could. You’d have to ask the Secret Service.”

“It’s not a bad idea, actually,” Trump added. “I wouldn’t mind, if you want to do that. I wouldn’t mind.”